Eloise Parry, who "had issues with bulimia", died at the Royal Shrewsbury Hospital in April after taking the tablets to lose weight.
Fiona Parry said: "Eloise decided that even though she'd been told DNP was dangerous, being slimmer was worth the risk. She was convinced that the dangers were being exaggerated.
"She weighed the pros and cons and made a bad choice, it cost her, her life", she added.
I would implore anyone even considering taking DNP or something similar not to do so. These substances are sold by people who don't care about your health, they just want your money...
Eloise had sent a message to her college lecturer on the morning of her death, which said "I think I am going to die".
"No one is known to have survived after being sick after taking DNP," she wrote from hospital.
The student's GP said that while Eloise was not addicted she had "no apparent ability" to stop taking the pills.
DNP, which is also available as a powder, is not a controlled substance despite being linked to several previous deaths in the UK and overseas.
The industrial chemical, which is unfit for human consumption, was the subject of an Interpol warning notice issued to 190 countries in May.
Senior Coroner for Shropshire, John Ellery, ruled that Eloise's death was an "accidental consequence", of taking DNP in relation to her eating disorder.
This is a clearly a dangerous, toxic and fatal substance which should not be accessible and certainly not to persons seeking online self-prescribed medication.
Mr Ellery said he will write to the health minister about his concerns, adding "if the minister considers it appropriate to see whether DNP should be a classified substance that would be an appropriate outcome from this inquest".